Bridge icing deterrent

ABSTRACT

This invention relates to the prevention of the pavement on bridges and overpasses from freezing before the pavement approaches thereto by the application of an insulating bed of an expandable or foamed resin to the underside thereof.

United States Patent Alspach BRIDGE ICING DETERRENT Inventor: Howard E.Alspach, 4399 W.

Lincoln Hwy., Gomer, Ohio 45809 Filed: Oct. 29, 1973 App]. No.: 410,381

US. Cl. 264/465; 14/6; 14/73;

264/35; 264/467; 264/50; 404/27 Int. Cl. B27D 27/00 Field of Search14/6, 73; 52/309, 404,

References Cited UNITED STATES PATENTS 6/1895 Platt 52/339 X 1 Sept. 16,1975 3,070,196 12/1962 Switzgable 52/404 3,110,981 11/1963 Lm'ncr 14/73X 3,122,073 2/1964 Masse 404/18 X 3,619,437 11/1971 McDonald... 52/309 X3,626,702 12/1971 Monahan 61/50 3,783,569 1/1974 Roussin 52/404 XPrimary ExaminerPaul R. Gilliam Assistant ExaminerDavid H. CorbinAttorney, Agent, or Firm-Francis M. Crawford [57] ABSTRACT Thisinvention relates to the prevention of the pavement on bridges andoverpasses from freezing before the pavement approaches thereto by theapplication of an insulating bed of an expandable or foamed resin to theunderside thereof.

3 Claims, 1 Drawing Figure BRIDGE ICING DETERRENT The present inventionrelates to the insulation of the undersides of highway bridges andoverpasses. More particularly, it relates to the prevention of thepavements on highway bridges and overpasses from freezing over beforethe freezing of the connecting highway roadbeds by the application tothe undersides thereof of an insulating bed of expandable or foamedresin, such as styrofoam.

It is well recognized that intermittent freezing and thawing greatlyincreases the hazards of winterdriving and it is estimated that 23,000accidents result annually from localized icing or frosting of bridge oroverpass decks. Most of these result from the fact that the pavement onbridges and overpasses can become coated with frost, ice or snow soonerand more often than their approach pavements, with the result that theunwary driver frequently skids upon entering the bridge or overpass. Themagnitude of this problem differs widely not only from state to state,but from location to location, or bridge to bridge. This is due to themicroclimate associated with an individual bridge, in part, as well asto other local and roadway and traffic conditions, bridge construction,and the like.

The above hazards result from the fact that particularly during the falland early winter and during warm periods during the winter the groundand roadbed contain sufficient heat so that ice and frost do not form asreadily thereon as on the bridges and overpasses which have noprotection on their undersides from the cold air and winds with theresult that frost and ice form more quickly on the roadbed over thebridges and overpasses, with the result that the motorist may pass froma relatively dry, safe roadway pavement onto a slick, icey bridge oroverpass pavement surface.

Numerous efforts have been made in the past to overcome these recognizedhazards of winter driving, as for example, by using special pavingmaterials on the paved surface of the bridge or overpass, such as,abrasives, cinders, crushed rock, or the like. Deicing chemicals, suchas sodium chloride and calcium chloride, have likewise been used.However, the latter are definitely detrimental to Portland cementconcretes and materially increase maintenance and repair costs becauseof accelerated scaling and spalling caused thereby. Techniques toprevent the formation of ice, frost and the like, such as heating thepaved surfaces of the bridges or overpasses by electricity or pipesembedded in the pavement carrying hot liquids have been tried. None ofthese procedures, however, has been completely satisfactory for variousreasons.

I have now discovered that the hazards resulting from the formation ofice, frost and snow on the pavements of bridges and overpasses can belargely and economically eliminated by the application to the undersidesthereof of an insulating material comprising an expanded or foamedresin. This results in keeping the temperature of the pavement on thebridge or overpass comparable to that of the pavements leading onto thebridge or overpass so that the motorist does not immediately pass from arelatively safe road pavement to a hazardous bridge pavement.

The types of expandable or foamed resins which may be suitably used asinsulating materials for the above purpose are well known to thoseskilled in the art and include such materials as polystyrene,polyurethane, polyethylene, cellulose acetate, epoxy, silicone andphenolic resins. For most purposes, however, it has been found mostpractical to use the material known in the trade as styrofoam, becauseof its availability and ease of application.

The methods of applying expanded or foamed resins are well known bythose skilled in the art and it is understood that the method ofapplication most suitable for a given instillation may be employed inaccordance with the present invention. Suitable methods includemechanical, physical or chemical foaming. In mechanical foaming, theresin, as a solution or emulsion in liquid form, is vigorously agitateduntil it becomes a foam of air bubbles. Fusing of the foamed resin isgenerally accomplished by heat leaving the foam in a solid foam form.Polyvinyl chloride foam is suitably prepared in this manner.

Physical foaming usually is accomplished by forcing compressed nitrogengas into molten resin; As the pressure is released the gas expands andfoams the resin.

I In chemical foaming a chemical which will form a gas is dissolved in aliquid resin. The resultant gas causes the resin to foam.

In applying the foamed resin insulation to the underside of bridges andoverpasses according to the present invention it is first necessary toprepare a form underneath the roadbed over the bridge or overpass tosupport the foamed insulation during application and setting thereof, aswell as to prevent easy removal of the insulation bed by vandals afterformation. This form can be installed in any convenient manner. However,a convenient and economical method of preparing a suitable formcomprises suspending bars on the lower I s of the I-beams supporting thebridge or overpass. Such suspension bars, suitably spaced from eachother, serve as supports for the bottom of the form, which may be of anyconventional material, such as a fine wire mesh through which the unsetfoam does not readily pass. Preferably, a coarse wire mesh is placed onthe supporting bars and over this is placed a thin, light, solid sheetof wood, paper or metal to support the insulation during formationthereof without substantial loss of the unset resin and which alsoserves as a protection after formation of the insulating bed.

When I-beams are not used in the construction of the bridge or overpasssupports for the lower side of the form may be constructed in variousmanners well known to those skilled in the art, it only being necessaryor desirable that the lower side of the form be at a distance from thepavement serving as the upper side of the form approximately that of thelower I s of the conventional I-beams used in constructing bridges andoverpasses, and of sufficient strength to support the insulating bedduring construction thereof. Generally, the forms may be constructed inany conventional manner well known to those skilled in theart.

Holes are left or made at intervals through the form so that tubes forthe admission of the unset foam into the space between the lower surfaceof the pavement and the above-specified supporting form. The number andspacing of these holes will be dependent largely upon convenience butshould generally be located within the range of a few feet from eachother so as to facilitate rapid filling of the form and completion ofthe formation of the insulating bed. If desired, but less conveniently,the holes for admission of the foamed resin into the form may be madethrough the pavement to be protected.

After completion of the above-described form, unset resin foam isintroduced into the form through the holes until the space formedunderneath the pavement by the form support described above iscompletely or substantially filled with the foamed resin, using any ofthe convential foamed resins and means for the formation of molded foamresin objects therewith. In the present instance, it is preferred to usea resin foam which sets without the application of heat. Such systemsare well-known to those skilled in the art.

The accompanying drawing will serve to illustrate somewhat more clearlythe instant invention. It is distinctly understood, however, that theclaimed invention is not limited to the exact means shown therein.

In the drawing, 1 represents a conventional I-beam used in theconstruction of bridges and overpasses. The pavement over the bridge oroverpass is represented by the numeral 2. The lower lip 3 of the l-bearnsupports the bars or slats 4 resting thereon and used as supports forthe coarse wire mesh 5 on which rests a thin layer of wood veneer, heavypaper or thin metal 6. The openings through the bottom of the form andthrough which the resin foam is introduced into the form are represented by the numerals 7 and the foamed resin filling the form by thenumeral 8.

The insulating effect of the insulating bed of set foamed resin 8 delaysthe cooling of the pavement 2 and the formation of ice and frost thereonat a rate faster than on the approach pavement so that the motorist willdrive onto a bridge or overpass pavement which is less slick than theapproach pavement, and thus materially reducing the usual hazards ofdriving over bridges and overpasses during periods of ice or frostformation.

What is claimed is:

1. Method for reducing the formation of localized ice and frostdeposited during freezing weather on pavements on roads over bridges andoverpasses supported on l-beams parallel to the direction of the road,which comprises constructing immediately underneath said pavements oversaid bridges and overpasses a box-like form of predetermined thickness,wherein the lower side of said box-like structure is a thin, light sheetof material capable of holding a resin during introduction and settingof same in said box-like structure, said sheet being supported on barsthe ends of which rest on the lower lips of the I-beams supporting thestructure on which the said pavements are laid, and the lower surface ofsaid pavement constituting the upper portion of said box-like structure,and introducing into said boxlike structure, through a plurality ofholes located in the bottom of said box-like structure a resin in fluidform selected from the group consisting of polystyrene,

polyurethane, polyethane, cellulose acetate, epoxy, silicone andphenolic resinous material in an amount sufficient to fill said box-likestructure completely when in foam form, converting said resin to foamform and permitting said foamed resin to set in solid form in contactwith the lower surface of said pavements constituting the upper portionof said box-like structure.

2. Method according to claim 1, wherein said sheet is supported by acoarse wire mesh resting on said bars the ends of which rest on thelower lips of said I-beams.

3. Method according to claim 1, wherein said sheet is a coarse wiremesh.

1. METHOD FOR REDUCING THE FORMATION OF LOCALIZED ICE AND FROSTDEPOSITED DURING FREEZING WEATHER ON PAVEMENTS ON ROADS OVER BRIBGES ANDOVERPASSES SUPPORTED ON 1-BEAMS PARALLEL TO THE DIRECTION OF THE ROAD,WHICH COMPRISES CONSTRUCTING IMMEDIATELY UNDERNEATH SAID PAVEMENTS OVERSAID BRIDGES AND OVERPASSES A BOX-LIKE FROM OF PREDETERMINED THICKNESS,WHEREIN THE LOWER SIDE OF SAID BOX-LIKE STRUCTURE IS A THIN, LIGHT SHEETOF MATERIAL CAPABLE OF HOLDING A RESIN DURING INTRODUCTION AND SETTINGOF SAME IN SAID BOX-LIKE STRUCTURE, SAID SHEET BEING SUPPORTED ON BARSTHE ENDS OF WHICH REST ON THE LOWER LIPS OF THE 1-BEAMS SUPPORTING THESTRUCTURE ON WHICH THE SAID PAVEMENTS ARE LAID, LAID, AND THE LOWERSURFACE OF SAID PAVEMENTT CONSTITUTING THE UPPER PORTION OF SAIDBOX-LIKE STRUCTURE, AND INTRODUCING INTO SAID BOX-LIKE STRUCTURE,THROUGH A PLUALITY OF HOLES LOCATED IN THE BOTTOM OF SAID BOX-LIKESTRUCTURE A RESIN IN FLUID FORM SELECTED FROM THE GROUP CONSISTING OFPOLYSTYRENE, POLYURETHANE, POLYETHANE, CELLULOSE ACETATE, EPOXY, SILICONAND PHENOLIC RESINOUS MATERIAL IN AN AMOUNT SUFFICIENT TO FILL SAIDBOX-LIKE STRUCTURE COMPLETELY WHEN IN FOAM FORM, CONVERTING SAID RESINTO FOAM FORM AND PERMITTING SAID FOAMED RESIN TO SET IN SOLID FORM INCONTACT WITH THE LOWER SURFACE OF SAID PAVEMENTS CONSTITUTING THE UPPERPORTION OF SAID BOX-LIKE STRUCTURE.
 2. Method according to claim 1,wherein said sheet is supported by a coarse wire mesh resting on saidbars the ends of which rest on the lower lips of said I-beams.
 3. Methodaccording to claim 1, wherein said sheet is a coarse wire mesh.